Decanter Centrifuges are the ultimate in solid liquid separation.  They can handle very high solid to liquid ratio and are truely continuous operation.  They can run days if not months without stopping.  Decanters can remove solids from liquids down to .003mm with concentration between 2 and 60% solids.  They are widely used in oil fields dewatering pumping mud, waste water treatment, sludge dewatering, food processing, ect.  Operation consists slurry pumped into the rotating drum and solids are separated to the outside surface due to centripetal force.  Also inside the drum is a auger moves the sedimented solids axial along the drum, up a "beach" and out the solids exit.  Meanwhile, the liquid flows out the opposite end of the drum.  Decanters are extremely adaptable and can be used in almost any sludge dewatering or solid separation application.